1. Field of the Invention
The present invention relates to a cap positioning construction for positioning one element of a barrel and a cap (hereinafter referred to as a mounted element) relative to the other element of the barrel and the cap (hereinafter referred to as a mounting element) by placing the mounting element on the end portion of the mounted element.
2. Description of the Related Art
A conventional a cap positioning construction of this type, has been described, for example, in Japanese Patent Publication Laid-Open No. 10-71796. In the cap positioning construction described in the above publication, an inclined engaging portion is formed on the inside face of either one element of a barrel and a cap, whereas a receiving portion with which the engaging portion engages is formed on the other element, and the engaging portion or the receiving portion formed in the cap is formed on the inside face thereof. In this construction, by engaging the engaging portion with the receiving portion, the cap is fixed to the barrel. In order to remove the cap from the barrel, the cap is turned relatively with respect to the barrel, and thereby the cap is moved along an inclined face on which the engaging portion and the receiving element slide each other so as to separate from the barrel, by which the cap can be removed.
However, in the conventional cap positioning construction as described above, the engaging portion or the receiving portion is formed on the inside face of the cap, which is problematic in that the engaging portion or the receiving portion is invisible from the outside, so that the operation for installing the cap is difficult.
Also, the conventional cap positioning construction is unsuitable for being used commonly for writing instruments of different types in which different internal mechanisms are incorporated in the same barrel. For example, when the construction is applied to a mechanical pencil, since a lead is generally refilled, the cap must be detachable from the barrel. Contrarily, when the construction is applied to a ball-point pen, since a refill is generally replaced by removing a tip end member on the tip end of the barrel, the cap is preferably undetachable from the barrel to prevent the cap from being lost. Thus, it is difficult to apply the cap positioning construction commonly to a mechanical pen and a ball-point pen.
In view of the foregoing and other drawbacks, disadvantages and problems of the conventional methods and structures, a first object of the present invention is to provide a cap positioning construction that makes easy positioning a cap to a barrel.
Another object of the present invention is to provide a cap positioning construction that enables a cap and a barrel to be used commonly for both of the positioning construction in which the cap is detachable from the barrel and the positioning construction in which the cap is undetachable from the barrel.
To achieve the above objects, the present invention provides a cap positioning construction for positioning one element of a barrel and a cap (hereinafter referred to as a mounted element) relative to the other element of the barrel and the cap (hereinafter referred to as a mounting element) by placing the mounting element on the end portion of the mounted element. A triangular notch is formed in either one of a portion of the mounted element which abuts on the end portion of the mounting element and the end portion of the mounting element, and a triangular extension extending toward the notch and matching the notch is formed in the other, so that the mounted element is positioned relative to the mounting element by fitting the extension in the notch. With this construction, the cap can be mounted on the barrel while viewing the extension and the notch, so that the mounting operation is easy.
In order to more surely fix the mounted element to the mounting element, either one element of the mounted element and the mounting element may be formed with an protrusion projecting toward the other element, and the other element may be formed with a concave portion for receiving the protrusion, so that the protrusion and the concave portion are engaged lightly with each other.
The cap positioning construction can further comprise a clip formed integrally with said cap extending from a peripheral face of said cap toward the barrel, wherein a fitting position where said extension is fitted in said notch is disposed on a back face side of said clip. With this construction, the fitting position in which the extension is fitted in the notch is hidden by the clip, so that the appearance is not impaired. The clip can also be operated as a guide when the mounting operation is performed.
Further, an operating element for operating an internal mechanism in the barrel can be disposed on the peripheral face of the barrel, which lies on almost the same line as the clip in the axial direction when the mounted element is positioned relative to the mounting element. With this construction, the positional relationship in the circumferential direction between the cap and the barrel is determined unequivocally by fitting the extension in the notch, and thus the positional relationship between the clip and the operating element disposed on the peripheral face of the barrel can be determined unequivocally, so that the clip and the operating element can be disposed on almost the same line in the axial direction. Thus, both of the clip and the operating element can be disposed at a position at which they do not interfere with fingers when operation is performed with the barrel being held by hand, so that the operatability can be improved.
An engaged portion for being engaged with an engaging portion formed at a part of an internal mechanism projecting from the end of the barrel may be formed on the inside face of the cap. By forming in the cap the engaged portion for being engaged with the engaging portion of the internal mechanism, the cap can be mounted via the internal mechanism so as to be undetachable from the barrel. Thus, the same barrel and the same cap can be used merely by changing the internal mechanism in the barrel in both of the case where the positioning is performed so that the cap is detachable from the barrel and the case where the positioning is performed so that the cap is undetachable from the barrel.
An engaging portion can be formed in a portion of an internal mechanism in the barrel, which projects from an end of said barrel, and an engaged portion can be formed on the inside face of said cap to be firmly engaged with the engaging portion. By engaging the engaged portion of the cap with the engaging portion of the internal mechanism, the cap can be positioned relative to the barrel via the internal mechanism so as to be undetachable from the barrel.
At least one window hole may be formed in said barrel, and at least one elastic protrusion, which is engaged with said at least one window hole and for being elastically displaced in a radial direction, may be formed at a part of said internal mechanism. With this construction, the internal mechanism can be fixed surely in the barrel.
The present disclosure relates to subject matter contained in Japanese Patent Application No. 2001-36203, filed on Feb. 13, 2001, which is expressly incorporated herein by reference in its entirety.